Quote:
Originally Posted by steeve
So, going down, mostly coasting in high gear, with motor on, I averaged 59 mpg according to the instrument readout; then on the return trip, going up the same section, I got 17 mpg. Averaging the two, comes out to about 38 mpg for the total 20 miles of equal distance, up and down hill driving.
|
Hi Steeve. You can't average mpg like that.
You got 17 mpg over 10 miles; you used about 0.59 gallon for that part.
You got 59 miles going down over 10 miles, that's 0.17 gallon.
So you used 0.78 gallon over the combined 20 miles, that's about 26 mpg, not 38.
If it were 38 over 20 miles then you'd use 0.53 gallon for the total stretch, that's less than the 0.59 gallon for just the uphill part. 0.06 gallon of fuel would have been magically added to your tank on the descent!
There's no simple way to calculate overall mpg other than dividing total distance for each section by the total fuel spent for each section.
Still, 26 mpg is better than 23!
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.